Red Hat Bugzilla – Bug 1334479
tuned realtime profiles need rcu_nocbs
Last modified: 2016-11-04 03:27:31 EDT
Description of problem: tuned realtime-virtual-{host|guest] have rcu_nocbs missing from boot/kernel parameters Version-Release number of selected component (if applicable): How reproducible: Steps to Reproduce: 1. Activate either realtime-virtual-host or realtime-virtual-guest profiles 2. Reboot 3. cat /proc/cmdline Actual results: rcu_nocbs=$isolated_cores is missing Expected results: rcu_nocbs=$isolated_cores is included Additional info: /usr/lib/tuned/realtime/tuned.conf needs to be updated to include: cmdline=isolcpus=${isolated_cores} nohz_full=${isolated_cores} rcu_nocbs=${isolated_cores} intel_pstate=disable nosoftlockup
Upstream commit adding the fix: https://git.fedorahosted.org/cgit/tuned.git/commit/?id=2d89b31cf9c19c6526a4a6136fdcc037a49b4256
*** Bug 1356717 has been marked as a duplicate of this bug. ***
As reported in bug 1356717, this issue is a blocker as you can't start VMs with the RT kernel starting with kernel-rt-3.10.0-439.rt56.327.el7.
We need this for 7.2.z too.
========================================= Verified in: tuned-2.7.1-2.el7.noarch tuned-profiles-nfv-2.7.1-2.el7.noarch PASS ========================================= # cat /usr/lib/tuned/realtime-virtual-host/tuned.conf | grep cmdline cmdline=isolcpus=${isolated_cores} nohz=on nohz_full=${isolated_cores} rcu_nocbs=${isolated_cores} intel_pstate=disable nosoftlockup # cat /etc/tuned/realtime-virtual-host-variables.conf isolated_cores=1 # tuned-adm profile realtime-virtual-host # reboot # cat /proc/cmdline BOOT_IMAGE=/vmlinuz-3.10.0-493.el7.x86_64 root=/dev/mapper/rhel_dell--pe--fm120--2c-root ro crashkernel=auto rd.lvm.lv=rhel_dell-pe-fm120-2c/root rd.lvm.lv=rhel_dell-pe-fm120-2c/swap console=ttyS0,115200n81 isolcpus=1 nohz=on nohz_full=1 rcu_nocbs=1 intel_pstate=disable nosoftlockup The same behavior is also for realtime-virtual-guest. ========================================= Reproduced in: tuned-2.5.1-7.el7.noarch tuned-profiles-nfv-2.5.1-7.el7.noarch FAIL ========================================= # cat /usr/lib/tuned/realtime-virtual-host/tuned.conf | grep cmdline cmdline=isolcpus=${isolated_cores} nohz=on nohz_full=${isolated_cores} intel_pstate=disable nosoftlockup # cat /etc/tuned/realtime-virtual-host-variables.conf isolated_cores=1 # tuned-adm profile realtime-virtual-host # reboot # cat /proc/cmdline # cat /proc/cmdline BOOT_IMAGE=/vmlinuz-3.10.0-493.el7.x86_64 root=/dev/mapper/rhel_dell--pe--fm120--2c-root ro crashkernel=auto rd.lvm.lv=rhel_dell-pe-fm120-2c/root rd.lvm.lv=rhel_dell-pe-fm120-2c/swap console=ttyS0,115200n81 isolcpus=1 nohz=on nohz_full=1 intel_pstate=disable nosoftlockup
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://rhn.redhat.com/errata/RHBA-2016-2479.html